First performed in 1986, a little over a year before his death, Morton Feldman's For Christian Wolff belongs with the other vast, obsessive scores of his final years, such as For Philip Guston and the Second String Quartet. This is a single movement for flute and keyboard (piano doubling celesta), lasting almost three hours. The sleeve notes characterise For Christian Wolff as a "garrulous masterwork". But garrulous seems a strange adjective to apply to a piece, written for one of Feldman's oldest friends and a close collaborator in the 1950s, that ekes out its thematic material with parsimonious rigour, reducing it to the barest minimum of pitches and intervals, often to just a rising or falling semitone or tone.
In such a vastly expanded musical landscape the smallest shift or inflection assumes huge significance, while the tonal variety Feldman wrings from this limited palette is extraordinary. That places enormous demands on the concentration of the players, and the flautist Dorothy Stone and keyboard player Vicki Ray maintain that unstintingly. They are let down by the recording, though, which places instruments in a rather crude, close perspective, so there is too little space around these pared-down sounds.